Positioning of contextmenu when using appendTo

[mrMarco]

When a selector has been assigned to the appendTo option, the context menu wasn't (always?) positioned at the cursor position.
This fix solves the problem.

[bbrala]

Thank you for the contribution. In the tests it breaks on what seems a lack of srcElement. I think srcElement is not the cross browser property for that. Shouldn't this just be .target?

[mrMarco]

@bbrala: You're right. that isn't browser-independant. I've changed the new lines slightly to solve that. The new lines are now like this:

var menuContainer = (e.data.appendTo === null ? $('body') : $(e.data.appendTo));
var srcElement = e.target || e.srcElement || e.originalTarget;
op.show.call($this, e.data,
$(srcElement).offset().left - menuContainer.offset().left + e.offsetX,
$(srcElement).offset().top - menuContainer.offset().top + e.offsetY);

I've also commited the file again with the above lines.

[bbrala]

This can be .target since jQuery normalizes the event.

[bbrala]

Thanks for the contribution, it has been merged.